(a) Field of the Invention
The present invention relates to a handover, and more particularly to a method of transmitting data in a handover between base stations.
This work was supported by the IT R&D program of MIC/IITA [2005-S-404-22, Research and development on 3G long-term evolution access system].
(b) Description of the Related Art
In general, in a next generation wireless communication system (3GPP), when a mobile terminal performs a handover between base stations, a gateway transmits data traffic by using a user plane connection interval (hereinafter referred to as “S1 interface”) between the gateway and the base station that is used in order to provide a flexible service to the base station. However, when the data traffic is transmitted from the gateway to the base station by using the S1 interface, a bi-casting transmission method is used in which the data traffic is transmitted to a serving base station providing a service to the mobile terminal and a target base station to which a handover of the mobile terminal is made. At this time, an overhead is generated due to bi-casting.
Further, when the handover of the mobile terminal is generated between a plurality of base stations, a forwarding path is lengthened. As a result, a packet transmission delay occurs until packets are reordered in a target base station to which a handover is made. In order to prevent the packet transmission delay, a method has been suggested in which switching is made in the gateway. However, according to this method, there is a problem in that another method needs to be additionally considered so as to reduce a packet loss, such as buffering of the gateway.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.